Physicists hope that a Grand Unified Theory will unify the strong, weak, and electromagnetic interactions. There have been several proposed Unified Theories, but we need data to pick which, if any, of these theories describes nature.

If a Grand Unification of all the interactions is possible, then all the interactions we observe are all different aspects of the same, unified interaction. However, how can this be the case if strong and weak and electromagnetic interactions are so different in strength and effect? Strangely enough, current data and theory suggests that these varied forces merge into one force when the particles being affected are at a high enough energy.

Current work on GUT suggests the existence of another force-carrier particle that causes the proton to decay. Such decays are extremely rare; a proton's lifetime is more than 10³² years.